1. Field of the Invention
The present invention relates to a joining structure for fitting parts or articles together, in particular, for use in the process of assembling component parts, such as interior parts of vehicles.
2. Description of the Related Art
In the production line of vehicles, it is repeatedly performed by workers to attach various kinds of interior parts such as console boxes and door linings to vehicle bodies. Those parts have to be infallibly attached in the predetermined positions. In addition, it is desirable to simplify and facilitate the work of attachment of the parts and to shorten the amount of time required for attaching the parts, especially when those parts are attached to mass-produced cars.
Japanese Patent Public Disclosure P2000-118318A discloses a structure for mounting a plate member on linings of a vehicle and a decorative component of a vehicle having the same structure. The plate mounting structure comprises a hook of a generally T-shaped cross section which is attached to a component part such as a door liner pad, a pair of stick-like guides formed on the hook or a substrate plate coalesced into the hook, and a hole formed in a member such as a door trim board. The hook of a T-shaped cross section has a head portion extending horizontally and a leg portion extending vertically. In addition, the pair of stick-like guides extend in parallel with the head portion of the hook. On the door trim board, a pair of protruding portions are formed beside the hole and a recess or slit is formed between the protruding portions to receive the leg portion of the hook therein. When mounting a decorative component such as the door liner pad on the door trim board, the head portion of the hook is inserted into the hole of the door trim board and then the hook is slid toward the protruding portions in order that the leg portion of the hook enter the recess or slit between the protruding portions. Thereby, the head portion of the hook is brought into contact with the upper surfaces of the protruding portions, while the pair of stick-like guides are brought into contact with the lower surfaces of the protruding portions. As a result, the protruding portions are wedged between the head portion and the stick-like guides so that the door liner pad of a decorative component is mounted on the door trim board of a vehicle.
The plate mounting structure disclosed in P2000-118318A has a structure that the head portion of the hook and the pair of protruding portions are interlocked to fix the door liner pad onto the door trim board. In order to enhance rigidity of the coupling arrangement between the door liner pad and the door trim board, it is, therefore, necessary to increase the thickness of the junction between the head and leg portions of the hook. In the event that the hook is molded from a synthetic resin and the thickness of the junction is increased, however, there is the possibility that a recess or so-called sink, a deformation or a crack is produced in the upper surface of the head portion when the junction between the head and leg portions are cooled down. If the sink, deformation and/or crack is formed in the upper surface of the head portion, the head portion has to be covered by another part to prevent the sink, deformation and crack from being exposed to the cabin of a vehicle. The sink, deformation and/or crack may be also formed in one side of the substrate plate, when the hook and the substrate plate was integrally molded from a synthetic resin and the leg portion of the hook coalesced into the other side of the substrate plate. In this case, it is also necessary to cover the defects on the side surface of the substrate plate by another means when the defected surface of the substrate plate is exposed to the interior of a cabin.
In addition, the plate mounting structure disclosed in Japanese Patent Public Disclosure P2000-118318A has a hole put through a member such as a door trim board, into which the head portion of the hook is inserted. The hole is left open after the head portion of the hook and the pair of protruding portions were interlocked to fix the door liner pad onto the door trim board. Therefore, the plate mounting structure cannot be used in the state that the member having the hole appears on the outside.
Furthermore, in order to fix the door liner pad onto the door trim board, the plate mounting structure mentioned above requires the following two steps of: inserting the head portion of the hook into the hole; and sliding the hook toward the protruding portions. The direction of inserting the head portion is at a right angle to the direction of sliding the hook. Consequently, the two steps have to be carried out as a discontinuous action. Therefore, the mounting work required for the plate mounting structure is not always efficient.